Athermal lens design is common in the optics industry. Athermal lenses are designed to maintain focus across an expected or required operational temperature range. For example, International Application No. PCT/EP2012/076,332, filed internationally Dec. 20, 2012, which is hereby incorporated by reference in its entirety for all purposes, describes an athermal lens arrangement and the optical features and principles of such arrangements. In typical athermal lens designs, a spring is used to preload a thermal spacer against a lens cell and the spacer is sized such that its length combined with its coefficient of thermal expansion (CTE) allows the lens to stay in focus across the expected or required operational temperature range of the camera. This type of design is typically used in infrared cameras, night vision optics, and can also be applied to the focus of the input beam into the optical parametric oscillator (OPO) in a laser system.
However, the necessity of springs in typical athermal lens designs lead to a number of problems. For example, the added steps of assembly of the spring, the lack of room in a compact design for the added parts, and the extra cost of including and accommodating for the spring. Additionally, reliability of the system may be impacted by the additional spring element in the design.
Embodiments of the present invention are directed to solving these and other problems, individually and collectively.